Hanna Instruments Testers

Chewyoda · June 11th, 2009

Does anyone have the Hanna Instruments Testers? If so does it work well? Is it worth the money?? And is it for salt or freshwater tanks?

Thanks in advance for your replies

dvc_r · June 11th, 2009

I have the Hanna pH tester, I tried it because I feel like I get color blind looking at the colors with the API. I still end up using it as a backup to my API tests. It's ok, you have to buy the ph calibrating liquid (and the refills). It is "too" accurate", measuring to the nearest hundredth, but never stays at one reading, it's always changing. I use it for freshwater, I can't see why you couldn't use it for salt water. I works on everything else (ie... bleach, milk, orange juice, soda

)

Chewyoda · June 11th, 2009

how much you pay for it?

dvc_r · June 11th, 2009

It was a while back, but I thing somewhere around $25-$30.

lew2000 · June 11th, 2009

i have Hanna's and Pinpoint for both FW and SW, a pH meter is the cheapest of the testing units - about 65.00 on sale. The reading change somewhat becuase of course water chemistry changes, and as water circulates you will get 100ths changes even on pH periodicaly with a short time frame.

dvc_r · June 11th, 2009

As a matter of fact, I'm using it as we speak (I mean write) to monitor the ph because I'm trying that "do-it-yourself" CO2 and I don't want to see the ph drop.

pepetj · June 11th, 2009

Most electronic pH meters require periodic calibration with buffer solutions rated at pH7.00, 10.01 and 4.01. The cheapest units only allow calibration at one point (usually at pH7.0). Not being careful with this procedure can (and most likely will) end up in misleading readings.

I purchased a hardy pocket pH meter from Oakton, the eco Testr pH2.
You can check it out here:
http://www.chemopharm.com.my/framewo...2018329954.pdf

I don't think it is necessary to have one of these meters for responsible fishkeeping since liquid reagent test work with great accuracy. pH stability is way more important than the actual pH value, given the fish are within their adaptable pH range.

Also keep in mind that good pocket pH meters display their values in 1/10th intervals, showing only the first decimal (say 7.0, 7.1, 7.2... not 7.03, 7.11, 7.19...) since this is not an ordinal dimensional scale but a logarithmic scale. I would think twice if two decimals are shown since this is more likely reflecting an artifact than accuracy.

I am no expert, just my opinion.

Pepe
Santo Domingo

lew2000 · June 15th, 2009

Quote:

Originally Posted by pepetj

Most electronic pH meters require periodic calibration with buffer solutions rated at pH7.00, 10.01 and 4.01. The cheapest units only allow calibration at one point (usually at pH7.0). Not being careful with this procedure can (and most likely will) end up in misleading readings.

I purchased a hardy pocket pH meter from Oakton, the eco Testr pH2.
You can check it out here:
http://www.chemopharm.com.my/framewo...2018329954.pdf

I don't think it is necessary to have one of these meters for responsible fishkeeping since liquid reagent test work with great accuracy. pH stability is way more important than the actual pH value, given the fish are within their adaptable pH range.

Also keep in mind that good pocket pH meters display their values in 1/10th intervals, showing only the first decimal (say 7.0, 7.1, 7.2... not 7.03, 7.11, 7.19...) since this is not an ordinal dimensional scale but a logarithmic scale. I would think twice if two decimals are shown since this is more likely reflecting an artifact than accuracy.

I am no expert, just my opinion.

Pepe
Santo Domingo

Just as a reference, even though the pH scale is logarithmic, this doesn't negate the value of carrying the reference to a point on the scale. The following definition:

A logarithmic scale is a scale of measurement that uses the logarithm of a physical quantity instead of the quantity itself.

Thus if the scale is defined you can carry it out to whatever definition is chosen - which is done for significant calculations.

As to why the meters, not just pH, but ORP, nitrate, etc, are carried out to 100 - most scientific meters are calibrated at the farthest extent that the meter can measure so that accuracy can be defined. Obviuosly the futher out smaller changes can be measured regardless of wether logrithmic or numeric values, the greater the accuracy can be assured that the intrument is performing accurately. 100th's (calibration) are all that are necessary for home equipment versus lab gear.

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